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91.
Router R1 sits inside OSPF area 1. Router R2 redistributes an E1 route into OSPF for
prefix 2.2.2.0/24, with external metric 20. Router R22 redistributes an E2 route for
the same prefix/length, external metric 10. Under what conditions will R1 choose as
its best route the route through R22?
- A.R1 will always choose the route through R22.
- B.As long as R1’s best internal OSPF cost to reach R22 is less than 10.
- C.As long as R1’s best internal OSPF cost to reach R22 is less than 20.
- D.R1 will never choose the route through R22 if the E1 route through R2 is available.
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Routers add internal and external costs for E1 routes and use only external costs for E2 routes, so the cost for the route through R22 will always be lower. However, for a given prefix/length, OSPF always prefers intra-area routes first, then interarea, then E1, and finally, E2, all regardless of metric. |
92.
Router R1 has been configured with the redistribute ospf 1 route-map fred command
under router eigrp 1 . The route map named fred needs to be configured to
match routes to determine which routes are redistributed into EIGRP. Which of the
following answers lists an item that cannot be matched by route map fred?
- A.Subnet number
- B.Next-hop router IP address of the route
- C.Whether the route is an E1 or E2 route
- D.The route’s tag
- E.The number of router hops between the router and the subnet
- Answer & Explanation
- Report
Answer : [E]
Explanation :
Explanation :
| Because OSPF does not use hop count as a metric, the information about the number of hops is not available in OSPF routes in the IP routing table. The other answers list items that can be matched with the route map match subcommand. |
93.
Router R1 is redistributing between two OSPF processes. Given the configuration
shown, which includes all commands in the route map named fred, which of the following
answers is true regarding the redistribution into OSPF process 1?
router ospf 1 redistribute ospf 2 match external 2 route-map fred ! route-map fred permit 10 match ip address 1 set metric-type type-1
- A.No routes are redistributed because a route cannot be both E1 and E2.
- B.Only OSPF E2 routes in the OSPF 2 domain will be considered for redistribution.
- C.Inside the OSPF 2 domain, any formerly E2 routes will become E1 routes
- D.Routes permitted by ACL 1 will be redistributed, regardless of whether the routes are E1 or E2 routes.
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| The external 2 parameters on the redistribute command act as matching logic. Only routes from the source routing protocol (in this case OSPF 2) that match this extra logic will be considered for redistribution by this redistribute command. The set metric-type type-1 route map subcommand sets the route type as it is injected into the destination routing protocol (in this case, OSPF 1); this logic is not used for matching the source routes. The routes permitted by ACL 1 will be redistributed, but only those that are also E2 routes from the (source) OSPF 2 domain. The redistribute function will not change the attributes of routes inside a single routing domain, but only in the destination routing domain (OSPF 1), so the configuration has no effect on the OSPF 2 routes that remain in OSPF 2. |
94.
Router R1 refers to route map fred when redistributing from EIGRP into OSPF. The
entire route map is listed next. Which of the following answers must be true based
on the configuration as shown?
route-map fred deny 10 match ip address one route-map fred deny 20 match ip address two route-map fred permit 100
- A.The third route map clause will allow any routes not already filtered by the first two clauses.
- B.Routes permitted by ACL “two” will be redistributed
- C.Routes denied by ACL “one” will be redistributed
- D.All routes will be filtered.
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| The deny clauses in the route map mean that the route map will filter routes matched by that clause. The permit or deny action of the referenced ACLs just defines whether the route is matched. So, routes permitted by ACL “two” will be matched and then filtered because of the route map clause deny action. Routes denied by ACL “one” simply do not match the route map clause numbered 10; such routes might or might not be redistributed depending on the next two clauses. Clause number 100 does not have a match command, meaning that it matches all routes not otherwise matched, with a permit action, allowing these routes to be redistributed. |
95.
On Router R1, process EIGRP 1 is redistributing routes from process OSPF 2, calling
route map fred with the redistribute ospf 2 route-map fred command. R1 has
learned intra-area routes for 10.1.1.0/24 and 10.1.2.0/24 in part because of the Type
2 LSAs known for each subnet. The route map filters route 10.1.1.0/24 and allows
10.1.2.0/24 through. Which of the following commands on Router R1 list subnet
10.1.1.0/24? (Choose two.)
- A.show ip route
- B.show ip eigrp topology
- C.show ip ospf database
- D.show ip eigrp topology 10.1.1.0/24
- Answer & Explanation
- Report
Answer : [A and C]
Explanation :
Explanation :
| The problem states that R1 has learned OSPF intra-area routes for 10.1.1.0/24, so show ip route will display that subnet. As an intra-area route based on a Type 2 LSA, the show ip ospf database command lists the summary of the LSAs, including the 10.1.1.0 subnet number for that Type 2 LSA. However, because the redistribution filtering discards subnet 10.1.1.0/24, this value will not be included in the EIGRP topology table. |
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